1. Field of the Invention
The invention relates to an optical disk drive and, more particularly, to an optical drive which can restrict the displacement of a tray in a body along the vertical direction.
2. Description of the Related Art
Please refer to FIG. 1, which is a structural schematic diagram showing a part of a conventional optical disk drive. The optical disk drive 100 includes a tray 110, a body 120 and two protrudent blocks B1 and B2. The body 120 includes a raiser 120a and a traverse 120b which are coupled to each other. The traverse 120b further includes a principal axis motor 120b1 and an optical reading head 120b2. The protrudent block B1 is provided at the back of the tray 110 (which is shown by the dotted line), and the protrudent block B2 is provided at the raiser 120a. 
The tray 110 is used to carry the optical disk (not shown) putted by the user and can enter in the body 120 or be ejected from the body 120 along a parallel direction (which is parallel to the y axis) shown by the double-arrow symbol A in FIG. 1. In addition, the relative driving mechanism is used, and then the raiser 120a can cooperate with the movement of the tray 110 to move transversely right and left synchronously (that is, parallel to the x axis). At that moment, the side of the traverse 120b which is coupled to the raiser 120a can correspondingly move up or move down via the guiding track design of the raiser 120a. When the tray 110 shown in FIG. 1 enters in the body 120 toward the +y direction, the raiser 120a moves toward −x direction to make the protrudent block B2 move to the position whose x axis coordinate is same with that of the protrudent block B1 and abut against the protrudent block B1 when the tray 110 is in the body 120.
Please refer to FIG. 2A, which is a schematic diagram showing that the tray in FIG. 1 is situated in the body. As shown in FIG. 2A, the protrudent blocks B1 and B2 abut against each other and are at the same x axis position, and then a fastening relation can be generated to protect the tray 110 from ejecting from the body 120 toward the −y direction to assure the safety of the optical disk and the normal operation of the principal axis motor 120b1, the optical reading head 120b2 and other relative mechanisms when the optical disk is read.
However, if an improper overlarge external force (for example, the optical disk explodes) is applied to the tray 110, the protrudent block B1 may be given a force to push against the protrudent block B2, and the protrudent block B2 or the raiser 120a may have displacement or deformation (for example, the raiser 120a may slope towards the −y direction), or even the tray 110 is given an acting force along +z direction, all the above may cause the protrudent block B1 to get over the protrudent block B2 and to be separated from the body 120.
Please refer to FIG. 2B, which is a schematic diagram showing the situation that the two protrudent blocks shown in FIG. 2A are separated from each other along the z axis. In the FIG. 2B, if an acting force F along +z direction is applied to the tray 110, compared with the FIG. 2A, the protrudent block B1 and the protrudent block B2 are separated from each other along the z axis, and the fastening range is greatly decreased, so that the protrudent block B1 can easily get over the protrudent block B2.
In addition, the protrudent block B2 also can be provided at the traverse 120b to achieve the design of fastening with the protrudent block B1, but the above problem also exists.